Magneto-optical properties for bulk Cd 0.63 − y Mn 0.37 Hg y Te single crystals

We investigated the magneto-optical properties of diluted magnetic semiconductor Cd 1 − x − y Mn x Hg y Te ( x ∼ 0.37 ) single crystals grown using a vertical Bridgman method. This material crystallizes in the zinc-blende structure for values of y ⩽ 0.07 . The band gap energy increases with increasing y ( ⩽ 0.03 ) , while decreases with increasing y ( ⩾ 0.03 ) . An anomalous behavior was also observed in the magnetic susceptibility and electrical resistivity. Faraday rotation as a function of photon energy with various Hg compositions for CdMnHgTe in the temperature range of 10 - 300 K has been measured. The Verdet dispersion curves were enhanced near the fundamental band gap energy. The Verdet constant becomes larger since the effect of the s p - d exchange interaction is enhanced as the temperature is lowered. At 10 K , the Verdet constants of the Faraday rotation for the samples with y = 0 , 0.01, 0.03, 0.05, and 0.07 were observed to be − 1.09 , − 2.57 , − 3.94 , − 0.97 , and − 0.87 deg ∕ G cm at 613 nm , respectively. The Verdet constant showed a maximum for the sample with y = 0.03 , and the value is approximately four times larger than that of the Cd 0.63 Mn 0.37 Te crystal. The Verdet constant has a maximum around Hg compositions with y ∼ 0.03 , and this result agrees well with the behavior of the magnetic susceptibility. This result reflects that Hg ion mediates and enhances the spin-spin interaction between Mn 2 + ions with increasing Hg composition up to y ∼ 0.03 .